Biography: John Harrison

JOHN HARRISON AND THE FINDING OF LONGITUDE

Longitude is one of the co-ordinates given around the globe to
help pin-point the location of a given place. The longitude planes
from pole to pole lengthways. Before the technology of the modern
world made calculating earth positions a simple task, the longitude
posed the greatest of sea-going problems and became the subject
of scientific and astronomical debate in the early eighteenth century.
Ships could easily lose themselves by not being able to calculate
the longitude and it has also caused many sea-going disasters.

In October 1707, the fleet of Admiral Sir Clowdisley Shovell were
wrecked off the Scilly through not being able to gauge the correct
longitude position of the fleet. Over two thousand men, including
Shovell, were lost. This brought the subject to the fore and in
July 1714, Parliament passed the Longitude Act. This convened a
Board of Longitude to examine the problem and set up a £20,000
prize for the person who could invent a means of finding longitude
to an accuracy of 30 miles after a six week voyage to the West
Indies. It also made minor awards for discoveries and improvements
to the general problem. The Board consisted of the Astronomer Royal,
the President of the Royal Society, First Lord of the Admiralty,
Speaker of the House of Commons, the First Commissioner of the
Navy Board and three professors of mathematics from Oxford and
Cambridge.

One method that was examined was the finding of longitude by astronomical
means. The Astronomer Royal, Nevil Maskelyne thought that lunar
tables charting lunar and star positions would be the answer to
the problem. He resolutely rejected the possibility that a mechanical
device could find solution to the longitude problem. This was to
cause much anger and bitterness between himself and John Harrison,
the man who produced the chronometer that finally solved the problem.

John Harrison was born in Foulby, Yorkshire on 24th March 1693.
He was the eldest son of a carpenter and joiner, serving Sir Rowland
Winn of Nostell Priory. Harrison received only a limited education
but had a keen interest in machinery. He was employed on an estate
in Lincolnshire and developed, with his brother, a series of clocks
that kept very accurate time. In 1715, they developed an eight
day clock, using wooden wheels. Later, in 1726, Harrison developed
a grid-iron pendulum to avoid problems in timekeeping due to variations
in temperature. He also invented a recoil escapement which meant
that parts of the clock did not need to be oiled. In August 1718,
he married Elizabeth Barrel and had a son, John born the following
year. Seven years later, she died. Not long after, he married for
the second time, to Elizabeth Scott and had another son, William
and a daughter, Elizabeth. His first son, John, died at the age
of 18 and William helped his father towards winning the prize.

The prize offered by the Board of Longitude was a tempting one
for Harrison and he set out to make a sea-going timekeeper that
could keep accurate time to claim the prize. It became his life-long
work. The idea was to be able to compare local time to that of
the pre-determined Greenwich time (which the timekeeper or chronometer
would be set to), and thus find the longitudinal position of
the ship.

In 1735, Harrison completed the first of his timepieces. It was
made of brass and wood and weighed 72lbs. The chronometer was sent
on a voyage to Lisbon to trial its accuracy. On its return, he
was awarded £500 from the Board as a minor discovery. Harrison
continued to improve his design and completed a second timepiece
in 1739. This was less cumbersome than his previous clock. He continued
to improve the design and his third timepiece, completed in 1749
was awarded the Copley Medal of the Royal Society.

His fourth timepiece, in the form of a pocket watch, was completed
in 1759, and was the one with which Harrison intended to claim
the prize. It was taken on board HMS Deptford for a voyage from
Portsmouth to Jamaica and his son, William, accompanied it, to
ensure that it was wound daily. The ship left in November 1761
and arrived in Jamaica on 26th March 1762. On arrival, the clock
was checked and found to be 1 minute and 54 seconds out, a matter
of 18 geographical miles. Harrison had succeeded and went to claim
his prize.

Maskelyne, however, refused to accept the mechanical device, and
being a more educated man than Harrison, was able to persuade the
Board not to award the prize. Harrison then petitioned Parliament,
who passed an Act specifically authorising £5000 to be awarded
to him. Harrison was still unsatisfied - he felt he should have
the whole prize as he had fulfilled the criteria of the Board.
To show that it was no fluke, William again took the timepiece
on another voyage to Barbados in 1764. This time the timepiece
was accurate within 10 miles, even better than before. Still the
Board refused to award the main prize although admitting that he
had proved that the clock was effective. Parliament again intervened.
It passed another Act to award £10000 on condition that Harrison
explained the principles of the chronometer in full and that, if
it could be replicated and work effectively by other craftsmen,
the remainder of the prize would be awarded. Harrison was bitter
at the way he was being treated, but agreed to the conditions.
An exact copy of the his fourth timepiece (known as H4) was made
by Larcum Kendal and was taken on Captain James Cook's second voyage
between 1772-1774.

In the meantime, he made a fifth timepiece. William wrote to George
III, whose interest in science was well known and had his own observatory
in Richmond, to ask if he would care to observe and judge the
timepiece for himself. The King took it to Richmond and was well
pleased with the accuracy it maintained. In 1773, he appealed directly
to the Prime Minister, Lord North on Harrison's behalf. In June
1773, Harrison was awarded £8750, totalling in effect the
prize money offered. However, the Board were careful to point out
that it was not the prize, but merely a bounty awarded by Parliament.
A new Act, repealing the previous one, set out new strict conditions
for the award of the prize money was passed - duplicate entries
were required, they had to undergo a full year's trial at Greenwich
and two voyages around Britain (one eastward and one westward),
followed by a long distance voyage (destination stated by the Board)
and followed by a year's post-voyage observation at Greenwich.
The prize money was never claimed!

On Cook's return, Harrison felt his efforts had been totally vindicated
as Cook extolled the virtues of the timepiece, and Cook had been
able to make the first, accurate charts of the South Sea Islands.
He was so pleased with the effectiveness of the chronometer, that
he took it with him on his third and final voyage.

John Harrison died on his 83rd birthday on 24 March 1776 at Red
Lion Square, London. He was buried in a vault in Hampstead church.
A tomb was later erected by his son, William. In 1879, the London
Company of Clockmakers reconstructed it as a mark of respect -
even though Harrison had not been a member. His wife, Elizabeth,
died a year later and William died in 1815.

The Longitude Act 1773 was repealed in 1828 and the Board of Longitude
was disbanded. Although the main prize was never actually awarded,
to all intents and purposes, Harrison had been the main winner.
In total, the Board had made disbursements of £100,000 in
the course of its life, the last being in 1815. After this, the
problem of longitude had been solved and disasters, such as that
that happened to Shovell's fleet, were no longer possible.